'use strict'

var whiteSpace = require('hast-util-whitespace')

exports.before = siblings(-1)
exports.after = siblings(1)

// Factory to check siblings in a direction.
function siblings(increment) {
  return sibling

  // Find applicable siblings in a direction.
  function sibling(parent, index, includeWhiteSpace) {
    var siblings = parent && parent.children
    var offset = index + increment
    var next = siblings && siblings[offset]

    if (!includeWhiteSpace) {
      while (next && whiteSpace(next)) {
        offset += increment
        next = siblings[offset]
      }
    }

    return next
  }
}